Backing for smooth surface coverings and process therefor



July 18, 1961 F. J. NAGEL ETAL BACKING FOR SMOOTH SURFACE COVERINGS AND PROCESS THEREFOR Filed Dec. 6, 1956 INVENTORS.

FRITZ J. NAGEL ALBERT H. FRENCH DONALD K. KEEL ATTORNE floors, walls and the like.

United States Patent 2,992,963 BACKING FOR SMOOTH SURFACE COVERINGS AND PROCESS THEREFOR Fritz J. Nagel, Reading, Pa., and Albert H. French, Kearny, andDonald K. Keel, Westfield, N.J., assignors to Congolenm-Nairn Inc., Kearny, N.J., a corporation of New York Filed Dec. 6, 1956, Ser. No. 626,653 15 Claims. (Cl. 162-168) This invention relates to smooth surface coverings for In particular, it relates to fibrous sheets suitable as backings for such coverings and to methods of producing them.

This application is a continuation-in-part of our copending application Serial No. 552,440 filed December jected to high temperatures" and stiairis, and it is important that the backing maintain its strength at the temperaures encountered.

At the present time, a large percentage of the surface coverings which comprise a decorative and wear-resistant layer bonded to a backing make use of a sheet of felted fibers as the backing material. Felt alone as obtained from a paper machine has little usefulness as a backing due to its low strength and poor moisture resistance. It is conventional that felt backing sheets be impregnated to render them water resistant and to provide the necessary strength. The most common saturant heretofore has been asphalt.

Asphalt saturated felt has been widely used but it has certain disadvanages. .At temperatures below normal room temperature, a sheet of asphalt saturated felt becomes hard and brittle and cannot readily be installed without damage. Also, asphalt saturated felt has impaired strength at the elevated temperatures required in producing certain types of surface coverings. In the production of surface coverings in which a wear layer upon a felt backing is fused, the product must be subjected to temperatures of 300 F. or higher for several minutes. In the production of linoleum, the product must be cured by being maintained at temperatures up to 180 F. for long periods of time. Commercially, this is done by suspending long loops of uncured linoleum within large bulidings called stoves. A backing with poor strength properties at these elevated temperatures has a tendency to stretch or even to break when maintained under these conditions. In addition, in the case of asphalt saturated felt, color bodies in the asphalt under the influence of elevated temperatures migrate to the wear layer and cause discoloration. Another disadvantage of asphalt saturated felt is its black color which can prove determinental from the standpoint of appearance and also due to its tendency to stain room surfaces with which it comes in contact during installation.

Considerable effort has been expended by workers in the field to discover a substitute for asphalt as a felt impregnant. Various drying oil compositions have been used and although felts made in this way are light in color, they require prolonged cure at elevated temperatures in order that the necessary properties of strength lee ' without discoloration of the decorative and wear-resistant layer of the product. A further object of the invention is to provide a fibrous backing which can be used in the manufacture of a surface covering product which possesses good cutting qualities. Another object is to provide a fibrous backing sheet for a surface covering product which will be flexible at 50 F. and have strength at elevated processing temperatures. A further object is to provide a fibrous backing which will be light in color and will not stain room surfaces during installation of the product- Other objects and the advantages of the invention will appear hereinafter.

In accordance with the invention, a sheet of felted fibers is produced containing a uniformly dispersed water insoluble resinous substance precipitated as agglomerates upon the fibers and which is uniformly impregnated with a thermoplastic network resin, thereby producing a product which is suitable as a backing for a decorative surface covering.

With reference to the drawing, FIG. 1 is a cross-sectional representation of a surface covering comprising a felt backing produced in accordancewith the invention.

FIG. 2 is a flow diagram of a method for preparing a felt backing sheet in accordance with the invention.

With reference to FIG. 1, a layer 1 of decorative and wear-resistant composition is bonded to a sheet 2 of felted fibers which comprises a plurality of interwoven individual fibers 3. These fibers are disposed within the sheet providing numerous voids or air spaces 4. Agglomerates 5 of resin appear upon the fibers and particularly in the vicinity of points of intersection of the various fibers within the sheet. A coating 6 of a thermoplastic network resin is disposed Within the sheet covering each of the individual fibers within the sheet. The network resin covers the fibers but does not completely fill the voids 4 within the sheet.

With reference to FIG. 2, cellulose fiber containing furnish is refined in the presence of large quantities of water in refining units 10 and 11. The stocks from the refining units pass to a mixing chest 12 where they are mixed with an emulsion of resin added from a mixing tank 13. The particulate resin is caused to precipitate onto the fibers by the addition of a precipitating agent from tank 14. The mixture is further refined and diluted with water in a mixing unit 15, after which it is deposited from a cylinder type felt-forming machine 16 onto a moving screen 17 where much of the water is removed. Additional water is removed as the sheet passes between pressure rolls 18 and drying is completed by passage of the sheet over drying cans 19. The dry sheet passes through a tank 20 which contains a thermoplastic network resin dissolved in an organic solvent. The solvent is removed by passing the impregnated felt between squeeze rolls 21 and under drying lamps 23, after which the treated sheet is rolled for storage into a roll 22.

Numerous fibrous materials can be used as furnish in preparing a fibrous sheet in accordance with the invention. The fibrous material used is normally cellulose in origin although other fibers can be used, including those of animal and mineral origin. The sources of cellulose can include cotton or other rag stock, wood pulp, including both ground wood and chemical wood pulp, paper, boxes or mixtures thereof in any proportions. In addition, fillers such as wood flour can be used, The furnish used for preparing the fibrous backing in accordance with the invention is broken up into fibers and clusters offibers in refining units such as Jordan mills, disc, hydraulic and rod mills. Jordan mills are most widely used. They consist of a horizontally positioned conical shell within which rotates a cone-shaped plug. The clearance between the shell and the plug governs the size of the fibers produced. The refining operation is conventionally carried out with a fiber content between about 2 percent and about 4 percent and preferably about 3 percent, with the balance water.

After the refining step, an emulsion of resin is added to the stock. This resin, hereinafter referred to as the particulate resin, is, in accordance with the invention, a polymeric material made by polymerizing compounds having from 2 to 10 carbon atoms which contain the vinyl group, that is, the H C=C group. Suitable particulate resins include thermoplastic resins such as polymerized vinyl chloride, polymerized vinylidene chloride, polymerized vinyl acetate, mixtures of these with each other, copolymers with each other and with other monomers which are copolymerizable therewith such as methyl acrylate, maleic acid, ethyl methacrylate, methyl methacrylate, chloromaleic acid, fumaric acid, and the like, polymerized acrylic and methacrylic acids, polymerized derivatives of these acids such as ethyl acrylate, methyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-propyl acrylate, and the like, mixtures of these with each other, copolymers with each other and with other monomers copolymerizable therewith, and other resins such as polyethylene, polystyrene, polymerized methyl styrene, and the like. Particulate resins can also include elastorneric resins such as butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, natural rubber, polymerized chloroprene, polymerized isoprene, rubbery polybutadiene, and the like.

In accordance with the invention, the particulate resin is added in the form of an emulsion, and thus the resin selected must be water dispersible and water insoluble. In addition, it should have a softening point in excess of 175 F. and preferably between 250 F. and 450 F. as measured by the ASTM Ring and Ball Method which appears on page 1668, Part III of the 1955 edition of A.S.T.M. Standards. The softening point by this method is defined as the temperature at which a disc of specified size of sample held Within a horizontal ring is forced downward a distance of one inch under the weight of a standard steel ball while the sample is heated at a prescribed rate in a bath. It is to be understood that the term softening point as used in the specification and claims refers to the temperature as determined by the aboveidentified ASTM Ring and Ball Method.

The emulsion of particulate resins used in carrying out the process in accordance with the invention normally contains from about 5 to about 25 percent resin in dispersed form, with the balance water and small amounts of dispersing agents and emulsion stabilizers. Suitable dispersing agents can include sodium oleate, sodium resinate, triethanolamine, sodium lauryl sulfate, diethylene glycol monolaurate, pentaerythritol monooleate, alkyl aryl polyether sulfonate, and the like. Suitable stabilizers can include casein, starch, bentonite, methyl cellulose, sodium carboxyl methyl cellulose and the like.

The quantity of particulate resin added in emulsion form is adjusted so as to equal about 3 to about 15 percent resin based on the Weight of dry felt. From 5 to percent resin based on the weight of dry felt has been found to be particularly effective.

In accordance with the invention, after the emulsion of particulate resin is thoroughly mixed throughout the body of the stock in the mixing chest, it is precipitated onto the fibers in the form of agglomerates of resin. This is done by the addition of well-known precipitating agents such as alum, sulfuric acid and the like. In some cases, precipitation can be effected by the presence in the mixing chest of precipitating agents which come into the system with the furnish or the water. In either case, the fine micron or submicron particles of particulate resin in the emulsion form agglomerates upon the fibers serving to partially bond the fibers together in the mixing chest.

Polymers and copolymers of vinyl acetate are particularly eifective in preparing felt backing sheets in accordance with the invention. Felt fibers are polar in nature as is polyvinyl acetate. During the felting process, it is normal for the fibers to join and cross at points of high polarity. Agglomerates of polymerized or copolymerized vinyl acetate tend to form fiber-resin-fiber bonds at points of polarity on the fibers, thus imparting strength to the product.

Normally, after the resin is precipitated, the stock is diluted still further with water until it has a solids content of about /2 to about 1 percent. It then passes to a conventional web-forming machine which can be either a cylinder machine, a Fourdrinier or other type papermaking machine. The bulk of the water drains from the mass of fibers through the moving screen of the webforming machine and additional Water is removed by passing the sheet between pressure rolls. The moist sheet then passes over a number of drying cans which are conventionally heated with steam or other heating fluid. The number of drying cans, speed of sheet travel, and temperature of heating fluid are adjusted so that a substantially dry sheet leaves the last drying can.

The dry sheet is then uniformly impregnated with a thermoplastic resinous substance which is referred to in the specification and the claims as a network resin. The network resin in accordance with the inventionis a thermoplastic resinous material which has a softening point as measured by the ASTM Ring and Ball Method of below about 160 F. Network resins which have softening points between 50 F. and F. are particularly efiective. Selected resinous fractions of petroleum, coal or coniferous origin or blends thereof are useful as network resins in accordance with the invention, with petroleum resins being particularly efliective. The resin can be obtained by extraction from a heavy resin-containing fraction of crude oil by any standard method of petroleum extraction. Resin can also be obtained by polymerization of polymerizable hydrocarbon fractions derived from any petroleum stock. Resinous deposits obtainable from natural or blown asphalts are suitable. Alternately, coniferous resins such as pine resins or ester gum presoftened with compatible plasticizers so as to have suitable softening points are also suitable. The resin used as a network resin can be a mixture of high and low softening point fractions such that the mixture has a softening point as prescribed above.

The thermoplastic resin for use as a network resin in accordance with the invention should be light colored and preferably should have a color value as measured on the Gardner Color Scale of less than 18. It should be stable at elevated processing temperatures. It is particularly important that the resin selected not decompose at elevated temperatures to yield objectionable color bodies. The stability should be such that there is no substantial color change when the resin is maintained at 300 F. for 2 minutes. This condition would occur in the felt backing during fusion of a vinyl wear layer upon the felt.

The resin is applied in the form of a solution in a suitable solvent such as petroleum naphtha, benzene, toluene, carbon tetrachloride and the like. Alternately, a fluid hot bath of the resin can be maintained through which the dry sheet of felt is passed. Using a hot molten treatment, the temperature of the molten resin bath will normally be abou 250 F. to about 325 F. In the impregnation step, the dry felt can be passed through a bath in which it is completely immersed in a supply of network resin. Alternately, the network resin can be applied to each surface of the sheet in turn, with the time of contact being adjusted so that the resin penetrates wihin the sheet from each surface leaving no unimpregnated zone within the sheet.

It has been found that a fibrous backing with satisfactory moisture resistance and with excellent cutting properties is produced when the backing contains at least percent and preferably from 25 to 45 percent thermoplastic network resin based on the eight of dry fibers. With amounts less than 10 percent, moisture resistance and cutting properties are adversely affected.

The impregnated fibrous sheet produced in accordance with the invention is characterized by being light in color, having good moisture resistance and good cutting properties, by being flexible at temperatures below room temperature yet strong at elevated processing temperatures. It is believed that the presence of the particulate resin in he form of agglomerates upon the fibers within the sheet is of particular significance. This condition can be obtained only by actually forming the agglomerates upon the fibers in the mixing chest prior to the formation of the fibrous sheet. If agglomerates of resin are added either to the furnish or to the stock in the mixing chest, the resin will act only as a filler, and a sheet of reduced strength will be produced. It is believed that the agglomerates of resin within the sheet upon the fibers form a large number of hinge-like junction within the sheet, thus imparting to the sheet excellent flexibility even at 50 F., at which temperature asphalt saturated feltbacked products are too stiff for satisfactory handling.

The fibrous backing sheet produced in accordance with the invention is thicker and less dense than paper. Felt sheets for use as backings for surface coverings have unique characteristics and as such are particularly suitable for this use. The physical characteristics of a fibrous sheet are often measured and reported as the gauge to weight ratio which is thickness of felt (inches) X1000 weight of 480 square feet of felt (pounds) For floor covering felt, this ratio ranges from 0.8 to 1.2 and preferably from 0.85 to 1.05. Paper rarely has a gauge to weight ratio exceeding 0.75. When referring to the gauge to weight ratio of fibrous backing sheets produced in accordance with the invention, the weight is the weight of the fibers themselves, not including the resins present. The backing sheet produced normally has a thickness of between 0.020 inch and 0.080 inch and preferably between 0.025 and 0.050 inch.

It is conventional that one or more seal coats be applied to the side of the impregnated felt which is to bear the decorative and wear-resistant layer. Seal coats can be either of the oleoresinous or latex type. In the case of a seal coat of the oleoresinous type, the vehicle can contain such drying oils and compatible resins as linseed oil, soybean oil, tung oil, China-wood oil, rosin, ester gum and the like. These oils and resins are dispersed in suitable solvents such as mineral spirits, turpentine, naphtha and the like. In the case of a seal coat of the latex type, the vehicle comprises an emulsion of such elastomers as natural rubber, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, and the like.

A size coating of thermoplastic or elastomeric resin can be applied to the surface of the felt which is to be adhesively bonded to the surface to be covered. This size coat is conventionally a dispersion of resin in a suitable solvent. It has been found to be particularly effective to employ the same resin used as the particulate resin in the felt as the resin in the size coat. The presence of the size coating on the back of a surface covering product tends to minimize fraying at the cut edges during cutting of the product during installation. The amount of size coat is preferably adjusted so that it be present as about 0.5 to about 3 percent resin solids based on the weight of the dry sheet.

A layer of decorative and wear-resistant composition.

is applied to the side of the backing sheet bearing the seal coat. This layer can comprise any of the well-known types used in the surface covering art. For example, a preformed sheet of linoleum composition comprising drying oil, resins and fillers can be bonded to the seal coat. Alternately, linoleum composition can be calendered directly to the felt. In this case, the seal coat is customan'ly omitted. Alternately, a thermoplastic resinous composition comprising such resins as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinylidene chloride-vinyl chloride copoly-mer and the like, plasticizers therefor and fillers can be bonded to the base. The decorative and wear-resistant composition can be bonded to the fibrous base without an adhesive, but an adhesive tackifier can be used if desired. The decorative layer can comprise conventional printing enamels applied by block printing, rotary or similar techniques either directly to the seal coat or to another sheet which in turn is laminated to the impregnated and sized fibrous base sheet. The printed decoration can be protected if desired by a clear wear layer comprising urea-alkyd resins, vinyl resins or the like.

The product comprising a decorative and wear-resistant layer bonded to a backing sheet. is subjected to heat in order to produce a product with satisfactory properties for use as a surface covering. In the case of linoleum, the product is seasoned by holding it at temperatures between about F. and about F. for from 2 to about 6 Weeks. When a printed decoration is applied to the fibrous backing sheet, the product must be dried to remove the solvent from the printing enamels. This is usually done by subjecting it to a temperature of about 150 F. for from about 12 hours to 3 days. In the case of thermoplastic resinous composition as a decorative and/or wear-resistant layer on a fibrous backing, the resinous layer must be subjected to fusing temperatures which range from 300 F. to 375 F. for from about 30 seconds to about 2 minutes.

Example I A fiber stock made up of a furnish consisting of 46 percent corrugated boxes and 54 percent new cotton cuttings was refined in a Jordan mill and blended in a mixing chest to produce a water slurry containing 2.5 percent solids. An emulsion containing 12 percent solids. of polymerized vinyl acetate (having a ASTM Ring and Ball softening point of 395 F.) was added to the mixing chest so that the amount of polymer equaled 8 percent of the dry weight of the fibers. The resin was caused to form agglomerates by the addition of 20 percent alum solution to the mixing chest. The resulting mixture was diluted to /2 percent solids and the dilute slurry was formed into a web on a single cylinder paper machine.

The web was dried and passed through a dip tank containing a resinous petroleum fraction as a 40 percent solids solution in petroleum naphtha solvent. The petroleum resinous fraction had the following properties:

Form Semi-solid.

Softening point 79 F. (ring and ball method). Color 14 (Gardner Color Scale).

Density 0.98 grams/cubic centimeter.

Ash content 0.3%.

Viscosity 98 Saybolt-Furol seconds 210 F.

The web after being passed through squeeze rolls con tained 35 percent petroleum resin based on the dry weight of the fibers. The web measured 0.043 inch in thickness and had a gauge to weight ratio based on the weight of resin-free dry fibers of 0.90. The impregnated web was dried on conventional drying cans and to one side thereof was applied a size coat comprising a 5 percent solution of polymerized vinyl acetate in organic solvent so that the coat consisted of 0.02 pound of polymerized vinyl acetate per square yard of felt. A layer of uncured linoleum composition was sheeted and bonded to the side of the felt opposite to that bearing the size coat, and the 7 product was cured in a store for 24 days at a temperature of 160 F.

Example 2 To the fiber stock as described in Example 1 was added an emulsion of vinyl acetate-maleic acid copolymer with the amount of polymer in the emulsion adjusted to be 7 percent of the weight of the dry fibers in the mixing chest. After resin agglomeration, sheet formation and drying in the manner described in Example 1, the web was impregnated with a 40 percent solids naphtha solution of petroleum resin having a softening point of 110 F. The web contained 30 percent of petroleum resin based on the dry weight of the felt. After drying by passing over conventional drying cans, the sheet was coated With a seal coat and a decorative design was applied thereto by printing. The decorative face was coated with a polyvinyl chloride containing composition. The product was then fused by being held at 350 F. for a minute and a half.

Example 3 To the fiber stock in the mixing chest as described in Example 1, an emulsion containing 20 percent solids of butadiene-acrylonitrile copolymer was added. After precipitation and sheet formation in the manner de scribed in Example 1, the web was passed through a tank containing a molten mixture of 30 parts hard pine resin and 70 parts nitrobiphenyl softener. The tank was maintained at 325 F. The web contained 10 percent butadiene-acrylonitrile copolymer and 35 percent plasticized hard pine resin based on the dry weight of the felt.

After the felt was dried, an oleoresinous seal coat in the amount of 0.5 pound of solids per square yard of felt was applied, after which a decorative design was printed on the seal coat by means of a block printing machine. The product was dried in an oven maintained at 150 F. for a period of 16 hours.

Example 4 A furnish consisting of 60 percent roofing rags and 40 percent ground wood was refined and diluted to 3 percent solids in the mixing chest in the manner described in Example 1. An emulsion of 15 percent solids of butadiene-styrene copolymer was added to the mixing chest in an amount of 12 percent based on the dry weight of the fibers in the mixing chest. After precipitation of the resin and formation of the web in the manner described in Example 1, the web was passed through a tank containing 45 percent solids naphtha solution of petroleum resin having a softening point of 115 F. The finished web measured 0.056 inch in thickness and had a gauge to weight ratio based on the dry weight of the fibers of 0.93. Particles of uncured linoleum composition were sheeted and bonded to the web to form a smooth sheet which was then cured at a temperature of 155 F. for 21 days.

Example 5 A furnish consisting of 100 percent corrugated boxes was processed in the manner described in Example 1. To the 2 percent solids slurry in the mixing chest an emulsion of polyvinyl chloride at a solids content of 25 percent was added. The amount of emulsion was adjusted so that 6 percent polyvinyl chloride was added based on the dry weight of the fibers in the stock. The stock was acidified by the addition of dilute sulfuric acid whereby the small particles of polyvinyl chloride in the emulsion formed aggl'omerates around clusters of fibers in the stock. After sheet formation in the manner described in Example 1, the web was passed through a tank containing a naphtha solution of light colored petroleum resinous fraction having a softening point of 110 F. The web contained 25 percent of petroleum resin based on the dry Weight of the fibers. To one side of the impregnated web,

after solvent removal, was applied a coating of a 2 per-.

cent solids solution of polyvinyl chloride in toluene so 8 that resin in the amount of 0.15 pounds per square yard of felt was added. After drying to remove the solvent, a sheet of polyvinyl chloride composition wear layer was laminated to the coated side of the felt.

Example 6 A furnish consisting of 60 percent rags and 40 percent corrugated boxes was processed in the manner described in Example 1. An emulsion of 8 percent polystyrene was added to the mixing chest and agglomerates of resin were formed upon the fibers under the influence of impurities in the slurry in the mixing chest. The amount of emulsion was adjusted so that 8 percent polystyrene was added based on the dry weight of the fibers in the stock. The stock was sheeted, impregnated with petroleum resin and used as a backing for a surface covering in the manner described in Example 5.

Example 7 A backing sheet was prepared in the manner disclosed in Example 1 except that the particulate resin was polymerized methyl methacrylate which was added to the stock as an emulsion of 15 percent solids. The amount of particulate resin in the felt was 9 percent based on the dry weight of the fibers. After sheeting, impregnation, and size coat application as described in Example 1, a layer of multi-colored granules of unfused polyvinyl chloride containing composition was applied to the side of the felt opposite to that bearing the size coat. The granules were consolidated in a press, after which the product was subjected to a temperature of 350 F. for 2 minutes for fusion of the polyvinyl chloride composition.

Each of the products prepared as described in the above examples was satisfactory as a surface covering product. In each case, the cutting properties were good. The products had good flexibility at temperatures below room temperature and also withstood elevated temperature processing conditions without damage. The backings prepared in accordance with Examples 1 and 2 proved particularly effective from the standpoint of flexibility, cutting properties and strength. The product prepared in accordance with the above examples were easily removable after the adhesive had set up, and, in addition, the time required for the adhesive to dry was less than that required by fully saturated asphalt impregnated felt products of the same type.

Any departure from the above description which conforms to the present invention is intended to be included within the scope of the claims.

We claim:

1. A resilient surface covering comprising a combination of a flexible backing sheet which is flexible at 50 F., strong at 300 F., and has good cutting properties and a decorative wear resistant layer secured to one surface of said backing, said backing comprising a fibrous felt sheet having distributed in the form of agglomerates on the fibers in the sheet about 3% to about 15% based on the dry weight of the fibers of a water dispersible and water insoluble resinous polymerized vinyl compound containi ing from 2 to 10 carbon atoms, and having said fibers and said polymer coated with at least 10% based on the dry weight of the fibers of a thermoplastic network resin having a softening point of less than F. selected from the groupconsisting of resinous fractions of petroleum and coal and coniferous resins, said network resin being light colored and stable at elevated processing temperatures.

2. A resilient surface covering comprising a combination of a flexible backing sheet which is flexible at 50 F., strong at 300 F., and has good cutting properties and a decorative wear resistant layer secured to one surface of said backing, said backing comprising a fibrous felt sheet having distributed in the form of ,agglomerates on the fibers in the sheet about 3% to about 15% based on the dry weight of the fibers of a water dispersible and water 9 insoluble resinous polymerized vinyl compound containing from 2 to 10 carbon atoms having a softening point of greater than 175 F., and having said fibers and said polymer coated with at least 10% based on the dry weight of the fibers of a petroleum resin having a softening point of less than 160 F.

3. The product of claim 2 wherein said resinous material is polymerized vinyl chloride.

4. The product of claim 2 wherein said resinous material is butadiene-acrylonitrile copolymer.

5. The product of claim 2 wherein said resinous material is butadiene-styrene copolymer.

6. The product of claim 2 wherein said resinous material is polystyrene.

7. The product of claim 2 wherein said resinous material is polymerized methyl methacrylate.

8. The product of claim 2 wherein said resinous material is a polymer of vinyl acetate.

9. The product of claim 2 wherein said resinous material is a copolymer of vinyl acetate and maleic acid.

10. A resilient surface covering comprising a combination of a flexible backing sheet which is flexible at 50 F., strong at 300 F., and has good cutting properties and a decorative wear resistant layer secured to one surface of said backing, said backing comprising a fibrous felt sheet having distributed in the form of agglomerates on the fibers in the sheet about 3% to about 15% based on the dry weight of the fibers of a water dispersible and water insoluble resinous polymerized vinyl compound containing from 2 to 10 carbon atoms having a softening point of greater than 175 F., and having said fibers and said polymer coated with about 25 to about 45 based on the dry weight of the fibers of a thermoplastic petroleum resin having a softening point of between about 50 F. and about 140 F., said petroleum resin having a Gardner Color of less than 18 and exhibiting substantially no color change when maintained at 300 F. for 2 minutes.

11. A resilient surface covering comprising a combination of a flexible backing sheet which is flexible at 50 F., strong at 300 F., and has good cutting properties and a decorative wear resistant layer secured to one surface of said backing, said backing comprising a fibrous felt sheet having distributed in the form of agglomerates on the fibers in the sheet about 5% to about based on the dry weight of the fibers of a water dispersible and water insoluble resinous polymerized vinyl compound containing from 2 to 10 carbon atoms having a softening point of about 250 F. to about 450 F., and having said fibers and said polymer coated with at least 10% based on the dry weight of the fibers of a petroleum resin having a softening point about 50 F. to about 140 F., said network resin bmeing light colored and stable at elevated processing temperatures.

12. In a method for producing a resilient surface covering comprising the steps of forming a web from a slurry of fibers, drying said web, impregnating said dry web with a water-proofing and strengthening impregnant and thereafter applying a decorative wear resistant layer to one surface of the impregnated web, the improvement which comprises precipitating from a water emulsion into said slurry from about 3% to about by weight, based on the dry weight of said fibers, of a water insoluble and water dispersible resinous vinyl polymer having a softening point of above 175 F., thereby causing said polymer to form agglomerates upon said fibers in a uniform manner, drying said web and uniformly impregnating said dry web with from at least 10% by weight, based on the weight of the dried fibers, of a thermoplastic resinous fraction having a softening point of below about 160 F. selected from the group consisting of petroleum fractions and coal and coniferous resins, said vinyl polymer being formed from a vinyl compound containing from 2 to 10 carbon atoms.

13. In a method for producing a resilient surface covering comprising the steps of forming a web from a slurry of fibers, drying said web, impregnating said. dry web with a water-proofing and strengthening inipregnant and thereafter applying a decorative wear resistant layer to one surface of the impregnated web, the improvement which comprises precipitating from a Water emulsion into said slurry from about 3% to about 15 by weight, based on the dry weight of said fibers, of a water insoluble and water dispersible resinous vinyl polymer having a softening point of about 175 F., thereby causing said polymer to form agglomerates upon said fibers in a uniform manner, drying said web and uniformly impregnating said dry web with from at least 10% by weight, based on the weight of the dried fibers, of a thermoplastic petroleum fraction having a softening point of below about F., said polymer being formed from a vinyl compound containing from 2 to 10 carbon atoms.

14. In a method for producing a resilient surface covering comprising the steps of forming a web from a slurry of fibers, drying said web, impregnating said dry web with a waterproofing and strengthening impregnant and thereafter applying a decorative wear resistant layer to one surface of the impregnated web, the improvement which comprises precipitating from a water emulsion into said slurry from about 5% to about 10% by weight, based on the dry weight of said fibers, of a Water insoluble and water dispersible resinous vinyl polymer having a softening point of about F., thereby causing said polymer to form agglomerates upon said fibers in a uniform manner, drying said web and uniformly impregnating said dry web with from about 25% to about 45% by weight, based on the weight of the dried fibers, of a thermoplastic petroleum fraction having a softening point of below about 160 F., said polymer being formed from a vinyl compound containing from 2 to 10 carbon atoms.

15. In a method for producing a resilient surface covering comprising the steps of forming a web from a slurry of fibers, drying said web, impregnating said dry web with a water-proofing and strengthening impregnant and thereafter applying a decorative wear resistant layer to one surface of the impregnated web, the improvement which comprises precipitating from a Water emulsion into said slurry from about 5% to about 10% by weight, based on the dry weight of said fibers, of a water insoluble and water dispersible resinous vinyl polymer having a softening point of from about 250 F. to about 450 F., thereby causing said polymer to form agglomerates upon said fibers in a uniform manner, drying said web and uniformly impregnating said dry web with from about 25% to about 45% by weight, based on the weight of the dried fibers, of a thermoplastic petroleum fraction having a softening point of from about 60 F. to about 140 F., said polymer being formed from a vinyl compound containing from 2 to 10 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 1,919,697 Groflf July 25, 1933 1,948,442 Ellis Feb. 20, 1934 1,956,866 Keller May 1, 1934 2,077,017 Schacht Apr. 13, 1937 2,170,755 Hanson Aug. 22, 1939 2,317,209 McCluer Apr. 20, 1943 2,399,804 Hills et al. May 7, 1946 2,656,296 Grangaard Oct. 20, 1953 2,681,599 Palese et al. June 22, 1954 2,723,195 Blake Nov. 8, 1955 2,789,903 Lukman et al. Apr. 23, 1957 2,791,502 Hess May 7, 1957 OTHER REFERENCES Oliner: The Properties of Flexible Impregnated Sheets, TAPPI Section, pages 73-80, Paper Trade Journal, vol. 125, No. 7, Aug. 14, 1947, pages 55-62. 

1. A RESILIENT SURFACE COVERING COMPRISING A COMBINATION OF A FLEXIBLE BACKING SHEET WHICH IS FLEXIBLE AT 50* F., STRONG AT 300*F., AND HAS GOOD CUTTING PROPERTIES AND A DECORATIVE WEAR RESISTANT LAYER SECURED TO ONE SURFACE OF SAID BACKING, SAID BACKING COMPRISING A FIBROUS FELD SHEET HAVING DISTRIBUTED IN THE FORM OF AGGLOMERATES ON THE FIBERS IN THE SHEET ABOUT 3% TO ABOUT 15% BASED MON THE DRY WEIGHT OF THE FIBERS OF A WATER DISPERSIBLE AND WATER INSOLUBLE RESINOUS POLYMERIZED VINYL COMPOUND CONTAINING FROM 2 TO 10 CARBON ATOMS, AND HAVING SAID FIBERS AND SAID POLYMER COATED WITH AT LEAST 10% BASED ON THE DRY WEIGHT OF THE FIBERS OF A THERMOPLASTIC NETWORK RESIN HAVING A SOFTENING POINT OF LESS THAN 160*F. SELECTED FROM THE GROUP CONSISTING OF RESINOUS FRACTIONS OF PETROLEUM AND COAL AND CONIFEROUS RESIN, SAID NETWORK RESIN BEING LIGHT COLORED AND STABLE AT ELEVATED PROCESSING TEMPERATURES. 